U.S. patent number 5,250,062 [Application Number 07/810,040] was granted by the patent office on 1993-10-05 for instrument for surgically correcting astigmatism.
Invention is credited to Khalil Hanna.
United States Patent |
5,250,062 |
Hanna |
October 5, 1993 |
Instrument for surgically correcting astigmatism
Abstract
The instrument comprises a tubular outer support forming a shell
around a determined axis and including a circularly symmetrical
annular base portion about the axis defining a substantially
spherical annular surface enabling the support to be pressed
against the cornea; the support includes a cylindrical inside wall
that is resiliently deformable in the radial direction to receive
the tubular top section of a template having a transverse wall at
its bottom which is delimited by a substantially spherical bottom
surface and which includes a central orifice and at least one pair
of arcuate slots disposed symmetrically about the center of the
wall.
Inventors: |
Hanna; Khalil (75007 Paris,
FR) |
Family
ID: |
9403465 |
Appl.
No.: |
07/810,040 |
Filed: |
December 19, 1991 |
Foreign Application Priority Data
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Dec 20, 1990 [FR] |
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90 16011 |
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Current U.S.
Class: |
606/166;
606/172 |
Current CPC
Class: |
A61F
9/013 (20130101); A61B 2090/3937 (20160201) |
Current International
Class: |
A61F
9/013 (20060101); A61F 9/007 (20060101); A61B
19/00 (20060101); A61B 017/32 () |
Field of
Search: |
;606/4,5,161,166,167,168,169,170,172,180 ;128/898,751,757,758
;604/22 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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147318 |
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May 1986 |
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EP |
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2364646 |
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Sep 1977 |
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FR |
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2242835 |
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Oct 1991 |
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GB |
|
Primary Examiner: Burr; Edgar S.
Assistant Examiner: Bennett; Christopher A.
Attorney, Agent or Firm: Sixbey, Friedman, Leedom &
Ferguson
Claims
I claim:
1. An instrument for surgery of the cornea to correct astigmatism,
the instrument comprising a template and a tubular outer support
forming a shell around a predetermined axis of the instrument
including a circularly symmetrical annular base portion about the
axis defining a substantially spherical annular surface for
contacting the cornea, said support including a resiliently
deformable cylindrical inside wall deformable in the radial
direction for receiving a tubular top section of said template,
said template having a substantially spherical bottom surface
including a central orifice and at least one pair of arcuate slots
disposed symmetrically about the central orifice.
2. An instrument according to claim 1, wherein the template
includes a mask for adjusting the annular length of the arcuate
openings, the mask being constituted by a tubular sleeve mounted to
rotate inside the tubular section of the template and including
radial wall portions at its bottom which overlie the slots and vary
the exposed amount of the slots depending on the angular position
of the sleeve in the tubular top section of the template.
3. An instrument according to claim 1, wherein the bottom surface
includes radial marks for determining the angular length of the
arcuate incisions to be made.
4. An instrument according to claim 1, wherein said template
includes an annular shoulder and the resiliently deformable
cylindrical inside wall is surmounted by the annular shoulder with
a top surface of the annular shoulder which is substantially
perpendicular to the axis including angular graduations.
5. An instrument according to claim 1, wherein the outer support
includes a pair of diametrically opposite handles that are
substantially parallel to a longitudinal axis of the instrument.
Description
BACKGROUND OF THE INVENTION
Various specialized instruments are presently available to the
surgeon for performing various cuts in the cornea as required by
surgery and/or trephination of the cornea. Thus, one such
keratotomy serves to make rediary incisions that are used, in
particular, for correcting myopia (short sight). Another is
designed to perform incisions that are transverse to a meridian of
the cornea, preferably in the form of circular arcs, for the
purpose of correcting astigmatism. There also exists an apparatus
for trephination of the cornea for transplanting purposes.
The most common need of an ophthalmological surgeon is an
instrument for surgical correction of astigmatism. This need is
satisfied at present only by one of the instruments outlined above
which are complicated and thus expensive and which are relatively
difficult to handle.
The invention seeks to provide a much simpler instrument for making
corneal incisions that are orthogonal to a meridian and that are
preferably arcuate so that the incision relates to a zone of the
cornea that is of substantially constant thickness. The simplicity
of the instrument makes it possible to reduce the cost thereof very
significantly, thereby making it available to a much larger number
of practitioners.
SUMMARY OF THE INVENTION
To this end, the present invention provides an instrument for
surgery of the cornea to correct astigmatism, the instrument
comprising a tubular outer support forming a shell around a
determined axis and including a circularly symmetrical annular base
portion about the axis defining a substantially spherical annular
surface enabling the support to be pressed against the cornea,
wherein the support includes a cylindrical inside wall that is
resiliently deformable in the radial direction to receive the
tubular top section of a template having a transverse wall at its
bottom which is delimited by a substantially spherical bottom
surface and which includes a central orifice and at least one pair
of arcuate slots disposed symmetrically about the center of the
wall.
Advantageously, the template includes a mask for adjusting the
angular length of the arcuate openings, the mask being constituted
by a tubular sleeve mounted to rotate with friction inside the
tubular section of the template and including radial wall portions
at its bottom which overlie the slots to a greater or lesser extent
depending on the angular position of the sleeve in the tubular
section of the template.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention is described by way of example with
reference to the accompanying drawings, in which:
FIG. 1 is an elevation view in half-section of an instrument of the
invention; and
FIG. 2 is a plan view of the instrument.
DETAILED DESCRIPTION
The support body 1 of the instrument shown in the figures comprises
an outer shell 2 that is generally frustoconical in shape and which
receives internally a complementary part 3 that is likewise
frustoconical, with the two parts being coaxial about an axis X.
When assembled together, these two parts define firstly a
substantially spherical annular surface 4 at the base of their
small diameter portion (i.e. the base portion of the support),
thereby forming a surface for pressing the instrument against the
sclera of the eye of a patient, and secondly they form an annular
chamber 5 between each other which opens out into the surface 4.
This chamber is designed to be connected by means of an endpiece A
to a vacuum source whose suction enables the support to be fixed on
the eye of the patient. In a simpler variant of the instrument, the
support may comprise a single piece only and its base portion may
include anchor claws for fixing it to the eye of a patient. In
another variant, the support may include both fixing means.
The inside piece 3 of the support has a cylindrical inside sleeve 6
which is deformable radially in resilient manner, thereby enabling
a guide template 7 to be fitted therein for making arcuate
incisions.
Above the sleeve,, the support includes a ring 8 whose top surface
is engraved with angular graduations 9. This ring may be moved
angularly by engaging a spike in drive orifices 10.
The support is also provided with instrument handles 11 and 12 that
extend upwards parallel to the axis X of the instrument.
The template 7 includes an axial sleeve 13 with a shoulder 14 at
its base to enable it to be fitted in the support. The sleeve 14
also includes a substantially spherical bottom wall 15 which is
provided with a central orifice 16 and at least one pair of
diametrically opposite arcuate slots. In the example shown in the
figures, the spherical wall includes two pairs of slots, with the
slots 17 of the first pair having a large mean diameter (e.g. 7 mm
or 8 mm), while the slots 18 of the second pair have a smaller mean
diameter (e.g. 5 mm or 6 mm). The angular extent of the slots is
identical (about 120.degree.). The width of the slots is equal to
the width of the surgical knife that is used for making the
incisions. For example, the knife may comprise a blade-carrier
having a flat that defines both the width of the knife (equal to
that of the arcuate slots) and the angular position of the
blade.
The template further includes a moving mask 19 which is constituted
by a cylindrical tubular portion 20 mounted for braked rotation
inside the sleeve 13 and having diametrically opposite radial
fingers 21 which are parallel to the curvature of the wall 15 of
the template and which are of sufficient length to extend past the
inside edges of the smaller slots 18. By rotating the mask relative
to the template, the fingers 21 are moved, which fingers constitute
adjustable moving ends of the arcuate slots. The surgeon can thus
delimit the length of the incisions that are to be performed.
Radial marks 22 serve to specify the selected angular length. The
surgeon can then locate the middles of the arcs and place the
template within the support by making said middles coincide with
the selected meridian.
* * * * *